The present invention relates generally to improved seal devices and, particularly, to a locking compressible plug assembly for hermetically sealing an opening in a part and locking the seal so formed.
The background information discussed below is presented to better illustrate the novelty of the present invention. This background information is not admitted prior art.
The problems presented by openings or holes in parts or devices, and attempts to solve these problems, i.e., the use of plugs or stoppers to seal the openings, have a long history. For example, in the age-old profession of wine and spirits making, “bung holes”, the holes drilled into beech wood casks used in the fermentation process, required plugs. These plugs were often made of materials such as cork and wood that would, with age rot and/or dry and shrink. And, as alcohols are still aged in wooden casks having bung holes, there is still a need for secure, reliable stoppers. As time and technology progresses, however, both the kinds of holes that need plugging and the means to plug those holes are becoming more sophisticated, and the need for a tight seal more demanding.
The plumbing industry is especially demanding in its needs for sealing plugs. Plumbers require sealing plugs when testing for leaks in drain and vent pipes and in the pipe connections of a plumbing system. To conduct mandated pressure tests, plumbers need plugs or stoppers to seal drain, waste, or vent pipes so that these pipes can be tested for their ability to withstand the predetermined internal pressures. In addition, plumbers, especially those that service the plumbing in our homes, have a need for inexpensive, yet reliable, plugs so that they can achieve the air-tight and liquid-tight conditions required for successful “plugging”. The pipes with which plumbing is constructed come in various sizes and are made of various materials, including cast iron, copper, clay, and polyvinylchloride accordingly the plugs and stoppers must be able to create the needed seal regardless of the size of the pipe or the material of which the piping is made.
The insulation industry also has a need for hermetically sealing plugs to plug the holes that are drilled into the side of houses and mobile homes during the installation of insulation material. After holes are drilled through which the insulation is installed, the holes must be plugged to protect the insulation from the environment and to keep it inside the wall space.
Containers, such as bottles, and especially containers carrying explosive or toxic materials require stoppers that will prevent their accidental removal and that will not allow the material to leak out of the container, especially during shipping.
The coating industry often is faced with applying a coating to parts, such as piping, but there are times when the coating must not be applied to the internal surface of the pipes. For example, when the coating would be incompatible with the fluids or gases that will come into contact with the internal surface area of the pipe, the internal surfaces of the pipe must be sealed off during the coating procedure. Thus, there is a need for the means to mask or to close the openings to prevent coating material from coming into contact with those parts that are not to be coated.
Environmental ground water monitoring requires not only tight sealing plugs, but also plugs that have the ability to be locked. When a spill is reported by a gas station, such as a leakage of gasoline from the station's underground gasoline storage tanks, for example, environmental regulations now require that monitoring wells be installed in the area of concern. The wells are used to collect ground water samples to first determine the extent of the spill and, subsequently, to monitor the success of the clean-up efforts or of the containment program.
Once a monitoring well is put into place, samples of ground water from each well are collected for testing to see if the contaminant is present in the ground water that flows into that well. It is well-accepted that this system works well, but only, of course, as long as no extraneous contaminant is allowed to enter into the well.
Often a monitoring well is placed in an area of heavy vehicular traffic. If a below-ground monitoring well opening is left uncapped, it is easy to understand how small amounts of gasoline, accidentally spilled onto the ground surface by a consumer filling his gas tank, could migrate beneath the ground surface and into the monitoring well. Thus, when a sample of water from that well is tested, the results would show the presence of gasoline in the groundwater, but there is no way to determine whether the gasoline had entered the well in ground water that was contaminated with gasoline from a leaking storage tanks or if the gasoline came from a small amount of surface run-off. Thus, monitoring wells need to be capped (plugged) to keep contaminants from entering the well.
Contamination can occur even when the well is capped. For instance, when the driver of a gasoline delivery truck mistakes the monitoring well inlet for a gas storage tank inlet and pumps the gasoline into the monitoring well. Such a mistake can lead to grave consequences as the gasoline mistakenly pumped into the monitoring well will quickly migrate away from the monitoring well and enter the ground water. In such a case, the need for a well cover that can be locked is apparent.
Sometimes the introduction of a contaminant into a monitoring well is deliberate. At best, this is done as a mischievous act; at worst, the motive is malevolent. In either case, deliberate contamination can destroy, at least a part of if not all of, a monitoring well program and could be prevented by the use of a hermetically sealed well cover that can be locked.
It is thus readily apparent that there is a need for an improved plug for pipes, a plug that can provide a hermetic seal, and that can be locked. There have been several attempts at fulfilling the need for a hermetically sealing plug that can be locked in the sealing position, but all such efforts to date have had serious drawbacks. Conventional plugs are available in many sizes and shapes and in many types of materials including, for example, cork, silicon, and rubber. Some are able to be locked.
Conventional plugs, however, provide a less-than-complete seal under certain circumstances. For instance, if a part has an opening into which a plug is inserted, and that part is to be heated, gas inside the void volume of the part will expand, potentially forcing the plug partially or completely out of the opening.
Another example occurs when the pipe end to be sealed is threaded. In this case, conventional plugs may form a less-than-complete seal around the threads, particularly where the threads are cut deeply into the walls forming the opening. This imperfect seal, especially in such a threaded opening, may permit liquids or gases to enter into, or if such is the case, escape from, the interior surface portions of the part by flowing along the incompletely plugged threads.
Conventional plugs that comprise an inflatable body are especially susceptible to leakage should the inflatable body develop a leak from any number of causes, including the body being over pressurized from either inside or outside of the body, where the body is exposed to caustic or acidic materials, or if the pipe, and thus the inflatable body, are subject to severe heating.
The construction of many of the conventional plugs is complex, thus the plugs are expensive to fabricate and assemble. In the cases where there are metal parts, these parts are subject to corrosion and subsequent failure. Some of the locking well caps have to be fitted around the top perimeter of the well piping and then cemented (grouted) in place, and in all cases the top of the sealing plug is flat. Flat topped plugs allow rain water or other fluids to remain on the top which would increase the physical or chemical weathering effects caused by the particular substance.
Some specialty plugs are designed to be totally water soluble, so that when the plug is no longer needed, it is broken inside the pipe and allowed to dissolve. This, of course, means that each plug can be used only one time.
Accordingly, it would be a significant improvement in the art to provide an improved sealing plug assembly that forms a hermetic seal between the plug and the interior surface of the opening to be sealed to prevent passage of liquids or gases through the sealing plug assembly with such plug being lockable so that only those who are entitled to break the seal and/or remove the plug can do so. The material used to manufacture an improved sealing assembly should allow the plug to expand if the opening that is sealed expands due to changes in environmental conditions or, alternatively, should permit the plug to contract if the sealed opening should contract. Additionally, an advantageously improved sealing assembly would be of simple construction, easy to make and use, reusable, not subject to rot or microbial degradation, would not transfer undesirable aromas and favors, and would be economical to manufacture.